| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hdfs.server.protocol; |
| |
| /* |
| * A system administrator can tune the balancer bandwidth parameter |
| * (dfs.balance.bandwidthPerSec) dynamically by calling |
| * "dfsadmin -setBalanacerBandwidth newbandwidth". |
| * This class is to define the command which sends the new bandwidth value to |
| * each datanode. |
| */ |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| import org.apache.hadoop.io.Writable; |
| import org.apache.hadoop.io.WritableFactories; |
| import org.apache.hadoop.io.WritableFactory; |
| |
| /** |
| * Balancer bandwidth command instructs each datanode to change its value for |
| * the max amount of network bandwidth it may use during the block balancing |
| * operation. |
| * |
| * The Balancer Bandwidth Command contains the new bandwidth value as its |
| * payload. The bandwidth value is in bytes per second. |
| */ |
| public class BalancerBandwidthCommand extends DatanodeCommand { |
| private final static long BBC_DEFAULTBANDWIDTH = 0L; |
| |
| private long bandwidth; |
| |
| /** |
| * Balancer Bandwidth Command constructor. Sets bandwidth to 0. |
| */ |
| BalancerBandwidthCommand() { |
| this(BBC_DEFAULTBANDWIDTH); |
| } |
| |
| /** |
| * Balancer Bandwidth Command constructor. |
| * |
| * @param bandwidth Blanacer bandwidth in bytes per second. |
| */ |
| public BalancerBandwidthCommand(long bandwidth) { |
| super(DatanodeProtocol.DNA_BALANCERBANDWIDTHUPDATE); |
| this.bandwidth = bandwidth; |
| } |
| |
| /** |
| * Get current value of the max balancer bandwidth in bytes per second. |
| * |
| * @return bandwidth Blanacer bandwidth in bytes per second for this datanode. |
| */ |
| public long getBalancerBandwidthValue() { |
| return this.bandwidth; |
| } |
| |
| // /////////////////////////////////////////////// |
| // Writable |
| // /////////////////////////////////////////////// |
| static { // register a ctor |
| WritableFactories.setFactory(BalancerBandwidthCommand.class, new WritableFactory() { |
| public Writable newInstance() { |
| return new BalancerBandwidthCommand(); |
| } |
| }); |
| } |
| |
| /** |
| * Writes the bandwidth payload to the Balancer Bandwidth Command packet. |
| * @param out DataOutput stream used for writing commands to the datanode. |
| * @throws IOException |
| */ |
| public void write(DataOutput out) throws IOException { |
| super.write(out); |
| out.writeLong(this.bandwidth); |
| } |
| |
| /** |
| * Reads the bandwidth payload from the Balancer Bandwidth Command packet. |
| * @param in DataInput stream used for reading commands to the datanode. |
| * @throws IOException |
| */ |
| public void readFields(DataInput in) throws IOException { |
| super.readFields(in); |
| this.bandwidth = in.readLong(); |
| } |
| } |